The covalency of nitrogen in $HNO_3$ is

Which of the following is the correct representation of the reaction when $BF_3$ reacts with ammonia?
$(i)$ $F_3B + :NH_3 \rightarrow [F_3B \leftarrow :NH_3]$
(ii) $F_3B + :NH_3$ $\rightarrow [F_3B$ $\rightarrow :NH_3]$

The unshared pair of electrons on a cyanide ion can act as

The bonds present in $N_2O_5$ are ........

Which of the following molecules does not contain a coordinate bond?

Give the structure of gaseous $AlCl_3$.